A GIS analysis of coastal development and trends in 

bottlenose dolphin strandings in Charleston, SC: 

implications for coastal marine spatial planning

NOAA Technical Memorandum NOS NCCOS 124
This report has been reviewed by the National Ocean Service of the National 

Oceanic and Atmospheric Administration (NOAA) and approved for 

publication. Mention of trade names or commercial products does not 

constitute endorsement or recommendation for their use by the United States 

government.

Green, M. A., McFee, W. E., and N. Levine. 2010. A GIS analysis of coastal 

development and trends in bottlenose dolphin strandings in Charleston, SC: implications 

for coastal marine spatial planning. NOAA Technical Memorandum NOS NCCOS 124. 

56 pp. 
A GIS analysis of coastal development and trends in

bottlenose dolphin strandings in Charleston, SC: 

implications for coastal marine spatial planning

Meredith A. Green1

, Wayne McFee2, and Norm Levine1

1

College of Charleston, 66 George Street, Charleston, South Carolina 29424

2

NOAA, National Ocean Service, National Centers for Coastal Ocean 

Science, Center for Coastal Environmental Health and Biomolecular 

Research, 219 Fort Johnson Road, Charleston, South Carolina 29412-9110

NOAA Technical Memorandum NOS NCCOS 124

December, 2010 

 

 United States Department of National Oceanic and National Ocean Service

 Commerce Atmospheric Administration

 Gary F. Locke Jane Lubchenco David Kennedy

 Under Secretary of Commerce

for Oceans and Atmosphere, Assistant Administrator

 Secretary NOAA Administrator (Acting)

1 

ABSTRACT

 Bottlenose dolphins (Tursiops truncatus) inhabit estuarine waters near Charleston, South 

Carolina (SC) feeding, nursing and socializing. While in these waters, dolphins are exposed to 

multiple direct and indirect threats such as anthropogenic impacts (egs. harassment with boat 

traffic and entanglements in fishing gear) and environmental degradation. Bottlenose dolphins 

are protected under the Marine Mammal Protection Act of 1972. 

Over the years, the percentage of strandings in the estuaries has increased in South 

Carolina and, specifically, recent stranding data shows an increase in strandings occurring in 

Charleston, SC near areas of residential development. During the same timeframe, Charleston 

experienced a shift in human population towards the coastline. These two trends, rise in estuarine 

dolphin strandings and shift in human population, have raised questions on whether the increase 

in strandings is a result of more detectable strandings being reported, or a true increase in 

stranding events. Using GIS, the trends in strandings were compared to residential growth, boat 

permits, fishing permits, and dock permits in Charleston County from 1994-2009. A simple 

linear regression analysis was performed to determine if there were any significant relationships 

between strandings, boat permits, commercial fishing permits, and crabpot permits.

The results of this analysis show the stranding trend moves toward Charleston Harbor 

and adjacent rivers over time which suggests the increase in strandings is related to the 

strandings becoming more detectable. The statistical analysis shows that the factors that cause 

human interaction strandings such as boats, commercial fishing, and crabpot line entanglements 

are not significantly related to strandings further supporting the hypothesis that the increase in 

strandings are due to increased observations on the water as human coastal population increases 
2 

and are not a natural phenomenon. This study has local and potentially regional marine spatial 

planning implications to protect coastal natural resources, such as the bottlenose dolphin, while 

balancing coastal development.
3 

INTRODUCTION

Coastal marine spatial planning (CMSP) is not a new idea but recently has become one of 

9 core areas outlined by the Interagency Ocean Policy Task Force (IOPTF; 2009). CMSP is an 

integrated, ecosystem-based process using the best technology and research available to 

determine the current and future uses of the coasts, oceans, and Great Lakes regions in order to 

minimize deleterious impacts and maintain sustainability (IOPTF 2009). A recent example of the 

benefits of MSP involved one of the most endangered whales, the North Atlantic right whale 

(Eubalaena glacialis), and the movement of a shipping lane in Massachusetts (MA). Past 

research on right whale distribution determined that these animals were sighted frequently in the 

shipping lane near Cape Cod, MA, increasing the risk of ship collisions. The movement of the 

shipping lane reduced ship collisions by 58%, while causing minimal delays to ship traffic 

(IOPTF 2009). 

The CMSP can create opportunities and incentives on a local level that can apply to a 

broader, regional level of similar concerns. Like right whales, bottlenose dolphins (Tursiops 

truncatus) inhabit coastal waters and are subjected to human activities including contaminant 

runoff, development, boat traffic, fishery operations, and others. 

Bottlenose dolphins are distributed throughout the world in temperate and tropical waters 

(Leatherwood and Reeves 1983). They can be found in harbors, estuaries, and river mouths 

among other habitats and have two distinct ecotypes, coastal and offshore (Gubbins 2002, 

Wilson et al. 1997). Some populations of dolphins have limited home ranges and others are 

migratory (Wilson et al. 1997). Along the east coast of the U.S. there is the coastal migratory 

stock (CMS) of bottlenose dolphins that range from the Florida Keys to Long Island, New York 

that comes through Charleston, SC (Zolman 2002). In addition to the CMS present in Charleston 
4 

there are also data showing the presence of a small community of year-round residents (Zolman 

2002; Speakman et al. 2006). When located near shore, resident populations of dolphins are 

potentially subjected to anthropogenic habitat alterations and increased human contact (Allen 

and Read 2000). 

Marine Mammals and Human Interaction

In coastal regions bottlenose dolphins are exposed to multiple direct and indirect threats. 

Threats of concern include: effects of anthropogenic chemicals (Hammond et al. 2008), reduced 

prey availability due to environmental degradation and overfishing, direct and indirect 

harassment caused from boat traffic, entanglements in fishery gear, and habitat destruction and 

degradation (Burdett et al. 2007, Hammond et al. 2008, Wells and Scott 1997). 

Due to increased boat usage in coastal areas over the years, there has been growing 

concern that this will result in more collisions with bottlenose dolphins (Figure 1) (Read 2008, 

Wells and Scott 1997, Nowacek et al. 2001). During the summer months the threat of dolphins 

colliding with boats increases significantly. There are several factors that contribute to this trend. 

First, from late spring through early autumn dolphins tend to shift their daily ranges from deeper 

coastal waters to shallow inshore waters and narrow channels (Constantine et al. 2004, Wells 

1993, Wells and Scott 1997). Second, tourism and major holidays during the summer greatly 

increase boat traffic (Wells and Scott 1997; Constantine et al. 2004). These factors make 

bottlenose dolphins more vulnerable to collisions with recreational boats (Wells and Scott 1997). 

The increased presence of boats in coastal habitats also alters the bottlenose dolphin

behavior by changing dive patterns and distribution (Nowacek et al. 2001; Hastie et al. 2003; 

Constantine et al. 2004; Lusseau 2005; Nowacek et al. 2007). In fact, Lusseau (2005) suggests 

that if a habitat becomes too populated with boats, dolphins will completely abandon the habitat 
5 

due to increased disturbance and harassment. It is in these waters where dolphins feed and rear 

calves. The increased presence of boats causes the shallow waters, once a safe haven, to be 

hazardous. 

The threat of entanglement in fishing gear is another hazard to marine mammals, 

including the bottlenose dolphin. Marine mammals and fisheries (commercial and recreational) 

directly interact with each other, often occupying similar geographic locations and competing for 

the same target species (Northridge 1984; Fertl and Leatherwood 1997; Northridge and Hofman 

1999; Friedlaender et al. 2001; Burdett et al. 2007). This can lead to marine mammal 

entanglement in fishing gear or ingestion of fishing gear (Mann et al. 1995; Knowlton and Kraus 

2001; Noke and Odell 2002; Burdett and McFee 2004; Burdett et al. 2007) (Figures 2 and 3). 

Other threats faced by bottlenose dolphin populations are the indirect threats caused by 

anthropogenic chemicals and environmental degradation (Hammond et al. 2008). A rise in the 

reporting of diseases in marine organisms has raised concerns that ocean health is deteriorating 

(Brouwer et al. 1989; Geraci et al. 1999; Harvell et al. 1999). There is a compelling body of 

evidence indicating that persistent organic pollutants can affect marine mammal immunity 

(DeSwart et al. 1994; Ross et al. 1995; Hammond et al. 2005). Schwacke et al. (2002) assessed 

reproductive risk in bottlenose dolphins and suggested that elevated PCB concentrations 

increased probabilities of first-born mortalities. Pathogens of terrestrial origin, such as 

Toxoplasma gondii, are causing disease in marine mammals and appear to originate in fresh 

water run-off (Miller et al. 2002, Stoddard et al. 2008). Thus anthropogenic effects on the ocean 

may cause an increase in disease outbreaks and deterioration of health in marine mammals 

(Gulland and Hall 2007). 
6 

Bioaccumulation of heavy metals through ingestion of food is also a great concern for the 

health of bottlenose dolphins (Beck et al. 1997). Metals such as mercury (Hg), cadmium (Cd), 

and lead (Pb) are toxic, with presence in the water being heavily influenced by anthropogenic 

run-off (Garcia and Millan 1998, Goyer 1991). 

Trends in South Carolina

Prior research on trends in bottlenose dolphin strandings in South Carolina has focused 

on life history parameters, population distributions, and natural and human-induced mortality 

rates (McFee and Hopkins-Murphy 2002, McFee et al. 2006, McFee and Burdett 2007). From 

1992-96, the mean number of strandings was 30.6/year; mean strandings per year increased to 

43.1 during the years 1997-2003 (McFee and Hopkins-Murphy 2002, McFee et al. 2006, McFee 

and Burdett 2007). Seasonal trends remained consistent between the two data sets, with 

strandings occurring more often in the spring and less in the winter. Strandings with evidence of 

human interactions (HI) also increased between the two studies, from a total of 25 during 1992-

96 to a total of 36 during 1997-2003. Both studies showed that HI strandings occurred most often 

during summer months and the main cause of death was fishing gear entanglements (McFee and 

Hopkins-Murphy 2002, McFee et al. 2006, McFee and Burdett 2007). In the 1992-96 study, 64% 

of HI cases and in the 1997-2003 study 44% of HI cases were a result of gear entanglements. It is 

during summer that recreational boating activities increase, thus increasing the likelihood of 

collisions, dolphin entanglement in fishing gear, and interaction with dolphin-watch tour boats.

Along the South Carolina coast there has been prior research focusing on bottlenose 

dolphin strandings associated with high tissue levels of contaminants. High levels of mercury 

have been found in livers of stranded dolphins in South Carolina (Beck et al. 1997). Mercury 

enters the environment through emissions from runoff, forest fires, and the burning of fossil fuels 
7 

and incineration of wastes (Goldwater 1971). High exposure to mercury for dolphins can cause 

death or lead to reproductive problems (Goldwater 1971). High levels of persistent 

organochlorines (POC), polybrominated diphenyl ethers (PBDE), perfluoralalkyl compounds 

(PFC), and other contaminants have been found in dolphins captured alive in the Charleston area 

(Hansen et al. 2004; Houde et al. 2006; Adams et al. 2008; Houde et al. 2009). 

In South Carolina, and many other regions of the United States, there is ongoing research 

analyzing trends in human population growth. Historically, South Carolina has experienced little 

growth, but starting in the 1970s urbanization increased dramatically due to immigration (Brown 

and Wardwell 1980). Over the last two decades, particularly in coastal regions, this trend has 

accelerated. In the Charleston region from 1973 to 1994 urban land use grew by 256% while the 

population grew by 41% (BCD COG 1997). By 2030 the projected population growth change for 

Charleston is expected to be 52.65% with an annual growth rate of 1.46% (Table 1, Figure 4). In 

addition, the urban area growth change is projected to be 185.64% with an annual growth rate of 

5.15% (Table 1, Figure 4). 

Urban growth is considered necessary for a sustainable economy, but uncontrolled or 

sprawling urban growth can lead to consumption of precious land resources such as rural land 

and marshes (Allen and Lu 2003). The projected population and urban growth in Charleston, SC 

may lead to more people living near marsh and estuarine areas resulting in more strandings being 

reported. The increase in population growth may also lead to increased runoff and environmental 

contamination which can affect a dolphin’s immune system (Beck et al. 1997, Allen and Lu 

2003).

This study investigated the relationships between dolphin strandings, human population 

densities, and human interactions near Charleston, SC from 1994-2009. An increase in reported 
8 

strandings has occurred near areas of residential development during this time. It is not clear if 

the increase in strandings is a result of human population shifts toward the coast, resulting in 

more reported strandings, or if the increase represents a real increase in the number of strandings 

(eg. emerging diseases, increase in boat collisions, pollution impacts, etc.). This study may have 

implications for marine spatial planning efforts on a local scale that may be applied statewide or 

regionally. 

METHODS

Stranding and Data Collection

Stranding data were collected by researchers at the National Oceanic and Atmospheric 

Administration (NOAA), Charleston, SC from 1994 to December 31, 2009. These data included: 

Species, Sex, Length, Location, Date, Season, Body Condition Code (1,2,3,4 or 5 with 1 being 

alive and 5 mummified), Human Interaction (Yes, No or Could Not Be Determined), Human 

Interaction Type (Crab pot, Gillnet, Boat Strike), Latitude, and Longitude. Stranded animals 

were also categorized as having been stranded in an estuary (estuarine) or on the front beach of 

barrier islands (beach). The GPS coordinates for each stranding were recorded in decimal 

degrees (DD). The time frame began in 1994 when stranding data were collected more 

thoroughly and on a consistent basis. Basic stranding demographics were initially divided into 

three sets: 1) mean strandings per year of all species that stranded in SC; 2) mean strandings per 

year of bottlenose dolphins in SC; 3) and mean strandings per year of bottlenose dolphins in 

Charleston County, SC. These means were used for two time frames: 1994 to 2001 and 2002 to 

2009. The analysis was repeated for animals involved with a human interaction. 
9 

 Boat registration data were collected through a Freedom of Information Act (FOIA) 

request to the South Carolina Department of Natural Resource (SCDNR). SCDNR was able to 

provide boat licensing data from 2002 to 2009 for Charleston County. The data included were 

year, county, and number of boat registrations. 

 Fishing license data were collected through a FOIA request to SCDNR. SCDNR was able 

to provide commercial (2002-2009) and recreational fishing licenses (2006-2009) for Charleston 

County. These data included year and number of commercial licenses and number of recreational 

licenses. Recreational fishing license data only went back to 2006 due to a recent purge in the 

SCDNR system under the SCDNR Document Retention Policy. 

Dock permitting data were collected under a FOIA request to the Ocean and Coastal 

Resource Management (OCRM). These data were requested for GIS use and thus OCRM 

provided the data as a feature class for the years 1994 to 2009 for Charleston County. The data 

were a point feature class. Each point represented a residency that obtained a dock permit for a 

designated year between 1994 and 2009. 

Residential data were collected from the Santee Cooper GIS Laboratory in downtown 

Charleston. These data were parcel data with a joined table. The table included a specific field 

for year built that allowed parcels to be shown by the year houses were built. The years ranged 

from 1994 to 2009 for Charleston County. These data were in polygon feature class form.

 The time frame from 1994 to 2009 was divided into four year intervals: 1994-1997, 

1998-2001, 2002-2005, and 2006-2009. This allowed trends to be observed at equal intervals and

to be more noticeable.
10

GIS Mapping

All data for this project used ArcGIS Software 9.3 (ESRI, Redlands, CA, USA). In 

addition all data used for the maps used the geographic coordinate system set to North American 

Datum 1983 and their projected coordinate system set to NAD UTM Zone 17N. Both the 

stranding data and dock permitting data were divided into the four year intervals. Each four year 

interval was then added to ArcMap using their coordinates to plot the locations. Both stranding 

and dock permitting data were then exported out of ArcMap into a geodatabase as a point feature 

class. 

 The general stranding maps consist of a base map of the South Carolina shoreline, 

obtained from the United States Geological Survey (USGS), zoomed in on Charleston. The 

stranding data were converted to point density data using kernel density located in the spatial 

analyst tools in the ArcMap toolbox. The kernel density data were set showing the density of 

strandings per square meter with a 6 km search radius. The symbology for the kernel density 

layer for each four year interval was set to the minimum-maximum type and the background 

value was set to equal zero. 

The dock permitting maps were created using a South Carolina base map obtained from 

NOAA’s Center for Coastal Environmental Health and Biomolecular Research (CCEHBR). The 

dock permitting point data were converted to point density raster datasets using kernel density, 

and was set with density showing docks per square meter with a 6 km search radius. The 

symbology was set the same way as the stranding density datasets were set. The dock permit 

densities are set to show cumulative growth. Stranding point data for each year interval were 

then overlayed on top of the dock density datasets with corresponding year intervals. 
11

There were two sets of residential growth maps. The first map used the South Carolina 

base map from USGS. The parcel data contains information on when homes were built and these 

data were used to show residential growth. However the data contains homes built ranging from 

1690 to 2009. Only homes built from 1994-2009 are shown on the maps. Homes built outside the 

time frame shown on the maps were removed from the symbology tab under layer properties and 

the remaining years were grouped. The residential growth data show cumulative growth from 

1994 to 2009. These data were then overlayed on top of the South Carolina base map and the 

stranding densities for the corresponding year interval were added. The second set of residential 

maps was created in case trends on the first set were not noticeable. The parcel data used for the 

first set were converted to points. These points were then converted to density rasters and then 

classified under the symbology tab. These data were then overlayed on top of the South Carolina 

base map and stranding densities for the corresponding year interval were added. 

Statistical maps were created using the raster datasets for strandings, dock permits, and 

residential growth. The raster datasets were classified under the symbology tab to standard 

deviation. The classified raster datasets for dock permits and residential growth were each 

overlayed on top of the classified raster datasets for strandings. These data were then overlayed 

on top of the South Carolina base map. 

Statistical Methods

The spatial statistics for strandings, dock permit growth and residential growth were 

created in ArcMap to show the standard deviations. Standard Deviation is a measure of 

dispersion of a set of data from its mean (Ramsey and Schafer 2002). The more spread apart the 

data, the higher the deviation. In order to map the spatial statistics for strandings, dock permit 

growth, and residential growth, to show the significance of the trends, only data greater than the 
12

standard deviation were shown. This resulted in maps showing trends that were outside the 

normal occurrences making them more significant. When the most significant regions for each 

dataset intersect they create a dark purple color that shows the overall most significant region. 

A Pearson correlation analysis was performed to determine if any of the factors that 

would be used in the regression analysis were strongly correlated with one another. If two factors 

were strongly correlated, then having both present for the regression analysis at the same time 

would give inaccurate results. The correlation analysis gives the Pearson correlation and the pvalue for each comparison. The Pearson correlation ranges from -1 to 1 where a value of 1 

implies a linear relationship, or strong correlation and a -1 implies an inverse linear relationship 

where the Y factor decreases as X increases (Ramsey and Schafer 2002). Having a Pearson 

correlation of 0 implies that there is no correlation between the two factors (Ramsey and Schafer 

2002). A p-value less than 0.05 was considered significant. 

A multiple linear regression model was then used for the analysis. Recreational fishing 

was left out of the statistical analysis because it only went as far back as 2006, whereas the boat 

data, commercial fishing data and crab pot permit data go back to 2002. If recreational fishing 

was included, the analysis could only go as far back as 2006 for all data (only four years), which 

is not enough data for a thorough statistical analysis. Including these data would impact the 

results of the analysis. 

 Another Pearson correlation analysis was performed to determine if there were any 

correlations between strandings, human interaction strandings (HI), boats, commercial fishing, 

recreational fishing and crabpot permits for Charleston County. A multiple linear regression 

model was then constructed to investigate the relationship between strandings, boats, commercial 

fishing, and crabpot permits for Charleston County from 2002-2009. A multiple linear regression 
13

model was also constructed to examine the relationship between HI strandings, boats, 

commercial fishing, and crabpot permits in Charleston County from 2002-2009. A second 

correlation analysis was performed to see if there were any correlations between total strandings, 

total crabpots, and total HI strandings. A multiple linear regression model was then constructed 

to investigate the relationship between total strandings and total crabpot permits from 2002-

2009. A fourth multiple linear regression model was constructed to examine the relationship 

between total HI strandings and total crabpot permits from 2002-2009. Total strandings, total 

crabpot permits and total HI strandings are referring to data that is state wide and not just in 

Charleston County. 

Stranding Graphs

Basic stranding graphs were created to show trends in strandings, HI strandings, 

commercial fishing, crabpot permits, and boat licenses. These graphs show strandings in 

Charleston versus total strandings in the corresponding year intervals as well as annually; HI 

strandings in Charleston versus total HI strandings in the corresponding year intervals as well as 

annually; total crabpot permits versus total strandings annually from 2002 to 2009; crabpot 

permits versus strandings in Charleston annually from 2002 to 2009; trends in Charleston 

commercial fishing licenses from 2002 to 2009; and trends in Charleston boat licenses from 2002 

to 2009. 

RESULTS

GIS Analysis

The stranding analysis in Figure 5 shows that from 1994 to 1997 the area around 

Sullivan’s Island (southeast of peninsula) had the most strandings. From 1998 to 2001 the 
14

densest areas of strandings remained around Sullivan’s Island, but also extended to the Isle of 

Palms (east of peninsula) area as well as near Seabrook Island (southwest of peninsula). From 

2002 to 2005 the densest area of strandings moved towards Charleston Harbor and up into the 

Ashley (northwest of peninsula), Cooper, and Wando Rivers. There also was a high density near 

Kiawah Island (southwest of peninsula). From 2006 to 2009 high density continued to move into 

the Charleston Harbor. There also was a high density of strandings near Folly Beach (south of 

peninsula) (aka Stono River Estuary) and Seabrook Island. 

 The trends in dock permitting versus strandings in Figure 6 show that from 1994 to 

1997 the densest areas for docks were located in the Wando River (northeast of peninsula), 

Charleston Harbor, Sullivan’s Island and Isle of Palms. There was also a high density of docks in 

the Stono River Estuary near Folly Beach. From 1998 to 2001 the densest areas for docks 

remained in the Wando River and the Stono River Estuary near Folly Beach. There is an 

increased number of strandings occurring up the Cooper River (north of peninsula), the Stono 

River Estuary, and in the Charleston Harbor (Figures 5, 6). From 2002 to 2005 a high number of 

docks remained in the Wando River with the Stono River Estuary and Charleston Harbor 

increasing. From 2006 to 2009 high dock densities increased in the Charleston Harbor, as well as 

near Isle of Palms, Wadmalaw Island (west of peninsula), Stono River Estuary and up the 

Wando River. 

The residential growth maps (Figures 7, 8) show that the greatest residential growth from 

1994 to 1997 is located in the Mt. Pleasant area followed by James Island (south of peninsula) 

and the West Ashley area. The greatest residential growth from 1998 to 2001 remained in the Mt. 

Pleasant area followed by James Island and the West Ashley area. From 2002 to 2005 

residential growth remained highest in Mt. Pleasant but was also high in West Ashley and James 
15

Island. Residential growth also increased in the Goose Creek area (north of peninsula). From 

2006 to 2009 residential growth remained highest in Mt. Pleasant, with Johns Island (southwest 

of the peninsula) showing growth as well. West Ashley and James Island also increased in 

residential growth. 

The maps comparing the significance between strandings and docks show that from 1994 

to 1997 strong correlations exist in locations near Sullivan’s Island, Isle of Palms and the Stono 

River Estuary near Folly Beach (Figure 9). From 1998 to 2001 the most significant regions for 

both docks and strandings were located near Sullivan’s Island, Isle of Palms, the Stono River 

Estuary near Folly Beach, and near Seabrook Island. The most significant regions for both docks 

and strandings from 2002 to 2005 were located in the Charleston Harbor, Sullivan’s Island, parts 

of the Stono River Estuary near Folly Beach, and near Seabrook Island. From 2006 to 2009 the 

most significant regions for both docks and strandings were in the Charleston Harbor, parts of 

the Stono River Estuary near Folly Beach, Isle of Palms, Sullivan’s Island, and a small region 

near Seabrook Island. 

The statistical maps comparing strandings and residential growth show that from 1994 to 

1997 strong correlations exist in locations near Sullivan’s Island, Isle of Palms, and the Stono 

River Estuary near Folly Beach (Figure 10). From 1998 to 2001 the most significant regions 

were located near the Stono River Estuary, Sullivan’s Island and Isle of Palms. The most 

significant regions for strandings and residential growth from 2002 to 2005 were located on 

James Island, Mt. Pleasant, and Sullivan’s Island. From 2006 to 2009 the most significant 

regions were located in the Charleston Harbor, Sullivan’s Island, and James Island. 
16

Spatial Statistical Analysis

The spatial statistics for strandings, dock permit growth and residential growth were 

mapped to show data greater than the standard deviation. The standard deviations for strandings 

are: 0.01867 for 1994-1997, 0.02399 for 1998-2001, 0.01934 for 2002-2005, and 0.01812 for 

2006-2009 (Figure 9). The standard deviations for dock permits are: 0.37574 for 1994-1997, 

0.83335 for 1998-2001, 1.46581 for 2002-2005, and 1.46581 for 2006-2009 (Figure 9). The 

standard deviations for residential growth are: 2.76541 for 1994-1997, 6.43772 for 1998-2001, 

10.09907 for 2002-2005, and 11.12970 for 2006-2009 (Figure 10). 

Pearson correlation analysis and associated p-values for multiple comparisons among 

strandings, HI strandings, boat licenses, commercial fishing licenses, recreational fishing 

licenses, and crab pot licenses for both Charleston County and South Carolina as a whole can be 

found in Table 2. There was no significant relationship between strandings and boat licenses 

(p=0.689), strandings and commercial fishing licenses (p=0.672), or strandings and crabpot 

permits (p=0.411). There was no significant relationship between HI strandings and boat licenses 

(p=0.377), HI strandings and commercial fishing (p=0.407), or HI strandings and crabpot 

permits (p=0.226). Likewise there was no significant relationship between total strandings and 

total crabpot permits (p=0.624) and total HI strandings and total crabpot permits (p=0.147). 

Stranding Analysis

 From 1994 to 2009, 638 bottlenose dolphin strandings were recorded in South Carolina. 

Of these, 332 were recorded in Charleston County. In Charleston County, from 1994 to 1997, 

37.2% of the bottlenose dolphin strandings occurred in the estuaries and from 1998 to 2001, 

38.0% occurred in the estuaries. Those percentages increased dramatically for the time periods of 

2002 to 2005 (51.3%) and 2006 to 2009 (51.8%). 
17

 Total strandings in South Carolina and strandings in Charleston follow similar trends

over the four year intervals (Figure 11). The lowest number of strandings occurs from 1994 to 

1997 while the highest number occurs from 1998 to 2001. Annual trends of total strandings in 

South Carolina versus strandings in Charleston follow similar trends (Figure 12). 

Figure 13 shows the total HI for South Carolina strandings versus HI strandings in 

Charleston divided into the four year intervals. The highest number of total HI strandings 

appears to be in both the 1998-2001 and the 2002-2005 intervals. The highest number of HI 

strandings in Charleston occurs in the 1998-2001 interval. The lowest number of total HI 

strandings occurs from 1994 to 1997 while for the HI strandings in Charleston the lowest occur

from 2002 to 2005. Figure 14 shows the total HI strandings versus HI strandings in Charleston 

annually with the peak number of strandings for both being in 1997 and the lowest being in 

2007. 

Figure 15 shows the total crabpot permits versus total strandings from 2002 to 2009. The 

highest number of crabpot permits is in 2004 while the highest number of strandings is in 2007. 

The lowest number of crabpot permits is in 2008 while the lowest number of strandings is in 

2002. Figure 16 shows the trends in crabpot permits in Charleston versus trends in strandings in 

Charleston from 2002 to 2009. The highest number of crabpot permits is in 2005 while the 

highest number of strandings is in 2009. The lowest number of crabpot permits is in 2008 while 

the lowest number of strandings is in 2005. 

Figure 17 shows the trends in commercial fishing licenses in Charleston County from 

2002 to 2009. The trend shows that there is a steady decline of commercial fishing licenses until 

2008 where licenses begin to rise. The peak number of commercial fishing license is in 2002 

while the lowest is in 2006. 
18

Figure 18 shows the trends in boat licenses in Charleston County from 2002 to 2009. 

The trend shows a steady rise in boat licenses from 2002 to 2007 with the peak being in 2007. 

The trend makes a sharp decline for 2008 and rises again in 2009. The lowest number of boat 

licenses occurred in 2002. 

DISCUSSION

While the total number of reported strandings in South Carolina has declined since 2001, 

recent stranding data (since 2001) shows an increase in strandings occurring near areas of 

increasing residential development in Charleston, SC. Reports of strandings in Charleston

estuaries increased nearly 50% in the last eight years of this study. It is not clear if the increase in 

strandings in estuaries is a result of human population shifts toward the coast, resulting in more 

detectable strandings, or if the increase represents a real phenomenon. This project served as a 

tool to evaluate the trends in strandings in relation to changes in residential growth and dock 

permitting in Charleston County from 1994-2009. The results of this project will be useful in 

detecting shifts in strandings in relation to increased coastal development.

Stranding Trends

The stranding trends from 1994 to 2009 clearly show increased stranding density moving 

into the Charleston Harbor and the Stono River Estuary (Figure 5). This may suggest that the 

increase in strandings is due to an increase in people living on the coast and more chance for 

observations. Based on the trends in Figure 6, dock growth is focused up the Wando River, 

Charleston Harbor, and the Stono River Estuary near Folly Beach. The dock growth appears to 

grow in the Charleston Harbor over the four year intervals and in the 2006 to 2009 year interval 

the Charleston Harbor seems to be the densest in docks. At the same time the stranding trend 
19

seems to gradually move into the Charleston Harbor and the Stono River Estuary. The number of 

people living in South Carolina estuaries has increased over the years due to land located in these 

areas being highly valued as sites for homes (Cofer-Schabica et al. 1999, Miller 1993). This 

increase in residence has also led to an increase number of requests for dock permits (NOAA 

2001). An increase in docks present in these habitats can potentially lead to more people 

overlooking the waters and increase the chance of spotting a stranding that in the past would not 

have been seen. 

An increase in docks can also provide easier boat access to the harbor, resulting in an 

increase in boat traffic and human interaction with dolphins. Two key elements in the CMSP 

process are to 1) engage stakeholders and the public during the CMSP process and 2) consult 

scientists and/or experts (IOPTF 2009). City planners should not only bring the stakeholders to 

the table when assessing dock needs and construction of new boat landings but also should bring 

scientists in on the process who are familiar with wildlife issues. For instance, the NOAA facility 

in Charleston has been conducting marine mammal stranding assessments since at least 1993 

(McFee et al. 2006) and photo-identification/population assessments on bottlenose dolphins in 

the Charleston Estuary since 1994 (Speakman et al. 2006). This would ensure support and 

cooperation throughout the development, implementation, and evaluation phases of a coastal 

marine spatial plan so that a determination of how these estuaries can be sustainably used and 

protected in the future (IOPTF 2009). 

The residential growth trends show that the Mt. Pleasant area remains fairly high in 

residential growth relative to other areas in Charleston County and appears to slowly grow from 

1994 to 2009 (Figures 7,8). James Island and Johns Island also seems to have increased

residential growth occurring from 1994 to 2009. Mt. Pleasant and James Island surround the 
20

Charleston Harbor where the stranding density is moving. The increase in residential growth, 

specifically in marsh front acreage, suggests that there may be more opportunity to detect 

strandings, as well as the possible increase in human interaction with dolphins. 

Statistical maps were created for docks and residential growth to see if the trends between 

them and strandings were significant (Figures 9, 10). The most significant regions for both 

docks and strandings are the Charleston Harbor and Stono River Estuary. The trend remained

stagnant around the Stono River Estuary except during the 2002-2005 interval where dock 

permitting may have decreased. However the trends for both docks and strandings are increasing

into the Harbor and up into the rivers surrounding Charleston. This suggests that the dock 

permitting trend and stranding trend correlate in the Charleston Harbor. 

Residential growth and strandings trends move from the Stono River Estuary and 

Sullivan’s Island areas towards the Harbor along the James Island side and Mt. Pleasant side. 

This suggests that both residential development and stranding density are gradually increasing in 

the Charleston Harbor. 

Allen and Lu (2003) and Campbell et al. (2001) show projected population growth up to 

the year 2030 based on current population trends. Table 1 shows the projected population growth 

change from 1994 to 2030 to be 52.65% with an annual growth rate of 1.46%. The projected 

urban area growth change is expected to be 185.64% with an annual growth rate of 5.15%. These 

data show that Charleston is expected to continue growing in population density and urban 

development. With stranding density trends moving into the Charleston Harbor, the projected 

increase in population and development along the coast may lead to an increase in sightings thus 

causing strandings to show an overall increase. 
21

The results of this study show that the stranding trend moves toward the Charleston 

Harbor over time and suggest that the increase in strandings is related to an increase in 

population and residential growth on the coast leading to strandings becoming more detectable. 

This suggests that more people are living in the areas where strandings occurred. The 

significance of docks can also suggest that boats have easier access to open waters which can 

increase the chance of human interaction. The factors that cause human interaction strandings 

such as boats, commercial fishing, and crab pot licenses are not significantly related to 

strandings, further supporting the hypothesis that the increase in strandings is due to increased 

opportunities for observations on the water and are not a natural phenomenon. 

HI Significance

Boat strikes, crabpot line entanglements, and other fishing gear related interactions are 

some of the main causes of HI strandings (Burdett and McFee 2004, Burdett et al. 2007, Fertl 

and Leatherwood 1997, Friedlaender et al. 2001, Knowlton and Kraus 2001, Mann et al. 1995, 

Noke and Odell 2002, Northridge and Hoffman 1999, Read 2008, Wells et al. 1998). Neither the 

correlation analyses nor multiple regression analyses showed any significant relationships 

between boat, commercial fishing, and crabpot licenses with strandings and HI strandings. This 

non-linear relationship supports the conclusion that the stranding trends are not a natural 

phenomenon, nor due to increased HI deaths. 

In addition, Figures 11 and 12 show that strandings in Charleston are following a similar 

trend to strandings statewide. Figures 13 and 14 also show that HI strandings in Charleston are 

following a similar trend to HI strandings statewide. These graphs point out that any noticeable 

increase in strandings in the Charleston area may not be an isolated occurrence but may be a 

statewide trend. Population growth is expected to increase in Charleston and South Carolina’s 
22

population is expected to increase on average 40,000 a year through 2025 (EPA 2008). Knowing 

the stranding and population trends are similar on a local and statewide level can help determine 

the causes of increased strandings and improve the CMSP process and marine mammal 

management. 

Figures 17 and 18 show the trends in Charleston commercial fishing licenses and 

Charleston boat licenses starting to increase in 2009. If this trend continues, it may lead to 

potential problems with increased strandings due to human interaction. However, based on our 

results, the increase in strandings in the estuaries may still be due to the increased coastal 

development and subsequent increase in human population density in coastal areas that will

allow for more observations in the creeks, rivers, and embayments. 

Marine Spatial Planning Implications

Bottlenose dolphins that live in a coastal habitat face disturbance from and interaction 

with human activities. This study showed that the detection of strandings in the estuaries 

increased as the human population and coastal development has increased in the Charleston 

Estuarine System (CES). We can project that at the current rate of coastal development in the 

estuaries more strandings will become detectable, thus increasing the pressure on stranding 

personnel to respond. This could be troublesome with dwindling budgets and reduced staff. 

Marine mammal strandings are high profile occurrences that generate public and media attention 

in South Carolina and other regions of the coastal U.S. Proper funding and appropriate staff 

levels will be necessary in the future to respond to the growing questions by the public and 

media on marine mammal mortality and to continue to use marine mammals as sentinels of our 

coastal oceans.
23

With increased development in the estuaries we are likely to see shifts in habitat 

preference due to increased siltation rates that may cause prey shifts and loss of habitat. This, in 

turn, could result in competition with humans for food resources as recreational fisheries (e.g., 

hook/line, crabpot) increase (Wells et al. 2008). 

With increased development comes the need to pave roads in new subdivisions that add 

contaminants to the estuaries through stormwater runoff. Similarly, the increased use of 

fertilizers and pesticides for residential lawns and pests may increase in the estuaries. This 

increasing contaminant load into the system could affect growth and reproductive fecundity of 

resident bottlenose dolphins. Previous studies on captured dolphins in the CES were shown to 

contain high persistent organic pollutants (Schwacke et al. 2002; Houde et al. 2005a), 

polybrominated diphenyl ethers (Fair et al. 2007; Houde et al. 2009), triclosan (Fair et al. 2010), 

and polyfluoroalkyl compounds (Houde et al. 2005b). Some of these contaminants are known to 

affect immune function, growth, and reproduction. 

While this study identifies the need to develop marine spatial planning mitigation 

strategies only in Charleston County, SC, the increased human population growth and 

development in other estuaries in SC, and in the southeastern U.S., will undoubtedly require 

mitigation strategies to protect our coastal natural resources.

ACKNOWLEDGMENTS

 The authors would like to acknowledge the staff of the Coastal Marine Mammal 

Stranding Assessments Program at NOAA/NOS/CCEHBR and the South Carolina Marine 

Mammal Stranding Network for assessment and response to marine mammal strandings. We 

would also like to acknowledge Cynthia Cooksey, Pete Key, and Marie DeLorenzo for their 
24

review of this manuscript and Debbie Lawson for administrative support. This project was 

funded in part by the College of Charleston and NOAA/NOS/CCEHBR. 
25

LITERATURE CITED

16 U.S.C. 1361 et seq. United States. Congress. Marine Mammal Protection Act. (MMPA) of 

1972 as Amended 2007. 

Allen, M.C. and Read, A.J. 2000. Habitat selection of foraging bottlenose dolphins in relation to 

boat density near Clearwater, Florida. Marine Mammal Science 16(4): 815-824. 

Allen, J. and Lu, K. S. 2003. Modeling and Prediction of Future Urban Growth in the Charleston 

Region of South Carolina: a GIS-based Integrated Approach. Conservation Ecology 8(2): 

1-17. 

Balance, L.T. 1992. Habitat use patterns and ranges of the bottlenose dolphin in the Gulf of 

California, Mexico. Marine Mammal Science 8(3): 262-274. 

Barlow, J., Swartz, S.L., Eagle, T.C., and Wade, P.R. 1995. U.S. Marine Mammal 

StockAssessments: Guidelines for Preparation, Background, and a Summary of the 1995 

Assessments. NOAA Technical Memorandum NMFS-OPR-6, pg.73. 

Barros, N.B. and Wells, R.S. 1998. Prey and feeding patterns of resident bottlenose dolphins 

(Tursiops truncatus) in Sarasota Bay, Florida. Journal of Mammalogy 79(3):1045-1059. 

BCD, COG. 1997. "Twenty Year Time Series Analysis of Satellite Remote Sensor Data for 

Environmental and Developmental Change along Coastal Georgia and South Carolina." 

Final report submitted to NASA via CD ROM.

Brown, D.L. and Wardwell, J.M. 1980. New directions in urban-rural migration: The population 

turnaround in rural America. Academic Press, Inc. New York, New York.

Beck, K.M., Fair, P., McFee, W., Wolf, D. 1997. Heavy metals in livers of bottlenose dolphins 

stranded along the South Carolina coast. Marine Pollution Bulletin 34(9): 734-739. 
26

Broadhurst, M.K. 1998. Bottlenose dolphins, Tursiops truncatus, removing by-catch from 

prawn-trawl codends during fishing in New South Wales, Australia Marine Fishery

Review 60(3): 9-14. 

Brouwer A., Reijnders, P.J.H., Koeman, J.H. 1989. Polychlorinated biphenyl (PCB) 

contaminated fish induces vitamin A and thyroid hormone deficiency in the common seal 

(Phoca vitulina). Aquatic Toxicology 15: 99-106. 

Burdett, L. 2003. An investigation of the blue crab (Callinectes sapidius) fishery as a potential 

source for bottlenose dolphins (Tursiops truncatus) in South Carolina. Master’s Thesis.

College of Charleston, Charleston, South Carolina. 

Burdett, L.G. and McFee, W.E. 2004. Bycatch of bottlenose dolphins in South Carolina, USA, 

and an evaluation of the Atlantic blue crab fishery categorization. Journal of Cetacean 

Research and Management 6(3): 231-240. 

Burdett, L.G., Adams, J.D., and McFee, W.E. 2007. The Use of Geographic Information 

Systems as a Forensic Tool to Investigate Sources of Marine Mammal Entanglement in 

Fisheries. Journal of Forensic Sciences 52(4): 904-908. 

Campbell, C.E., Passmore, S., and Allen, J. 2001. Charleston Urban Growth Model Used to 

Identify Resources at Risk. Proceedings of the Twenty-First Annual ESRI User 

Conference, 2001. 

http://proceedings.esri.com/library/userconf/proc01/professionalpapers/pap324/p324.htm. 

Accessed on May 31, 2010. 

Cato, J.C. and Prochoska, F.J. 1976. Porpoise Agency, London, U.K. pg. 63. 
27

Cofer-Shabica, S., Hackett, J., Phillips, F., Phipps, G., Reynolds, W., Robinson, H. 1999. The 

citizen’s guide to the Charleston Harbor project. Office of Ocean and Coastal Resource 

Management, Charleston, SC. Pg. 76. 

Constantine, R., Brunton, D.H., and Dennis, T. 2004. Dolphin-watching tour boats change

 bottlenose dolphin (Tursiops truncatus) behavior. Biological Conservation 117:299-307. 

DeSwart, R.L., Ross, P.S., Vedder, L.J., Timmerman, H.H., Heisterkamp, S., Van Loveren, H. 

1994. Impairment of immune function in harbor seals (Phoca vitulina) feeding on fish 

from polluted waters. Ambio 23:155-159. 

Environmental Protection Agency (EPA). 2008. Population Projections for South Carolina to 

2025. www.epa.gov/ttn/naaqs/ozone/areas/pop/popp_sc.pdf. Accessed on May 31, 2010. 

Everitt, R., Beach, R., Geiger, A., Jeffries, S., Treacy, S. 1981. Marine mammal-fisheries

interactions on the Columbia River and adjacent waters, 1980. Washington Game Dept. 

Olympia. pg. 109. 

Fair, P.A., Mitchum, G., Hulsey, T. C., Adams, J., Zolman, E., McFee, W., Wirth, E. and G. D. 

Bossart. 2007. Polybrominated diphenyl ethers (PBDEs) in blubber of free-ranging 

bottlenose dolphins (Tursiops truncatus) from two southeast Atlantic estuarine areas. 

Archives of Environmental Contaminants and Toxicology 53: 483-494. 

Fair, P. A., Lee, H., Adams, J., Darling, C., Pacepavicius, G., Alaee, M., Bossart, G. D., Henry, 

N., and D. Muir. 2010. Occurrence of triclosan in plasma of wild Atlantic bottlenose 

dolphins (Tursiops truncatus) and in their environment. Environmental Pollution. In 

Press.

Fertl, D. and Leatherwood, S. 1997. Cetacean interactions with trawls: a preliminary review. 

Journal of Northwest Atlantic Fishery Science 22: 219-248. 
28

Friedlaender, A.S., McLellan, W.A., Pabst, D.A. 2001. Characterising an interaction between 

coastal bottlenose dolphins (Tursiops truncatus) and the spot gillnet fishery in 

southeastern North Carolina, USA. Journal of Cetacean Research and Management 3(3): 

293-303. 

Garcia, R. and Millan, E. 1998. Assessment of Cd, Pb, and Zn contamination in roadside soils 

and grasses from Gipuzkoa. Chemosphere 37(8): 1615-1625. 

Geraci, J.R. 1989. Investigation of the 1987-88 mass mortality of bottlenose dolphins along the 

U.S. Central and South Atlantic coast. Final report to National Marine Fisheries Service 

and U.S. Navy, Office of Naval Research and Marine Mammal Commission, Washington 

D.C., January, 1989. 

Geraci, J.R., Harwood, J., Lounsbury, V.J. 1999. Marine mammal die-offs. Conservation and

Management of Marine Mammals, pg. 367-395. 

Goble, D. D. and Freyfogle, E.T. 2002. Wildlife Law. Foundation Press, New York, New York.. 

Goldwater, L.J. 1971. Mercury in the environment. Scientific American 224(5): 15-21. 

Gorzelany, J.F. 1998. Unusual deaths of two free-ranging Atlantic bottlenose dolphins

 (Tursiops truncatus) related to ingestion of recreational fishing gear. Marine Mammal

Science 14(3): 614-617. 

Goyer, R.A. 1991. Toxic effects of metals. In Casarett and Doull’s Toxicology: the Basic

 Science of Poisons. Pergamon, New York, pp. 623-680. 

Gubbins, C. 2002. Use of home ranges by resident bottlenose dolphins (Tursiops truncatus) in a

 South Carolina estuary. Journal of Mammalogy 83(1): 178-187. 

Gulland, F.M.D. and Hall, A.J. 2007. Is marine mammal health deteriorating? Trends in the 

global reporting of marine mammal disease. EcoHealth 4: 135-150. 
29

Hammond, J.A., Hall, A.J., Dyrynda, L. 2005. Comparison of polychlorinated biphenyl (PCB) 

induced effects on innate immune functions in harbour and grey seals. Aquatic 

Toxicology 74: 126-138. 

Hammond, P.S., Bearzi, G., Bjorge, A., Fortney, K., Karczmarski, L., Kasuya, T., Perrin, W.F., 

Scott, M.D., Wang, J.Y., Wells, R.S., and Wilson, B. 2008. Tursiops truncatus. In: IUCN 

2009. IUCN Red List of Threatened Species. Version 2009.1. www.iucnredlist.org. 

Accessed on February 26, 2010. 

Harvell, C.D., Kim, K., Burkholder, J., Colwell, R.R., Epstein, P.R., Grimes, J. 1999. Emerging 

marine diseases-climate links and anthropogenic factors. Science 285: 1505-1510. 

Hastie, G.D., Wilson, B., Tufft, L.H., Thompson, P.M. 2003. Bottlenose dolphins increase 

breathing synchrony in response to boat traffic. Marine Mammal Science 19(1): 74-84. 

Hastie, G.D., Wilson, B., Wilson, L.J., Parsons, K.M., Thompson, P.M. 2004. Functional

 mechanisms underlying cetacean distribution patterns: hotspots for bottlenose

 dolphins are linked to foraging. Marine Biology 144: 397-403. 

Honda, K., Tatsukawa, R., Itano, K., Miyazaki, N., Fujiyama, T. 1983. Heavy metal 

concentrations in muscle, liver, and kidney tissue of striped dolphin Stenella 

coeruleoalba and their variations with body length, weight, age and sex. Agriculture and 

Biological Chemistry 47: 1219. 

Houde, M., Hoekstra, P.F., Solomon, K.R., Muir, D.C.G., 2005a. Organohalogen contaminants 

in delphinoid cetaceans. Reviews of Environmental Contamination and Toxicology 184, 

1–57.Houde, M., Wells, R., Fair, P., Bossart, G., Hohn, A., Rowles, T., Sweeney, J., 

Solomon, K., Muir, D., 2005b. Polyfluoroalkyl compounds in free-ranging bottlenose
30

dolphins (Tursiops truncatus) from the Gulf of Mexico and the Atlantic Ocean. 

Environmental Science and Technology 39, 6591–6598. 

Houde, M., Wells, R., Fair, P., Bossart, G., Hohn, A., Rowles, T., Sweeney, J., Solomon, K., and 

D. Muir. 2005b. Polyfluoroalkyl compounds in free-ranging bottlenose dolphins 

(Tursiops truncatus) from the Gulf of Mexico and the Atlantic Ocean. Environmental 

Science and Technology 39, 6591–6598. 

Houde, M., Pacepavicius, G., Darling, C., Fair, P. A., Alaee, M., Bossart, G. D., Solomon, K. R., 

Letcher, R. J., Bergman, A., Marsh, G., and D. C. G. Muir. 2009. Polybrominated 

diphenyl ethers and their hydroxylated analogs in plasma of bottlenose dolphins 

(Tursiops truncatus) from the United States east coast. Environmental Toxicology and 

Chemistry 28: 2061-2068. 

Ingram, S.N. and Rogan, E. 2002. Identifying critical areas and habitat preferences of

 bottlenose dolphins Tursiops truncatus. Marine Ecology Progress Series 244: 247-255. 

Interagency Ocean Policy Task Force (IOPTF). 2009. Interim framework for effective coastal 

and marine spatial planning. The White House Council on Environmental Quality, 

December 9, 2009. 32 pp. 

Knowlton, A.R. and Kraus, S.D. 2001. Mortality and serious injury of northern right whales 

(Eubalaena glacialis) in the western North Atlantic Ocean. Journal of Cetacean Research 

and Management 2: 193-208. 

Krahn, M.M., Ylitalo, G.M., Burrows, D.G., Calambokidis, J., Moore, S.E., Gosho, M., Gearin, 

P., Plesha, P.D., Brownell, R.L.J., Blokhin, S.A., Tilbury, K.L., Rowles, T., Stein, J.E. 

2001. Organochlorine contaminant concentrations and lipid profiles in eastern North 
31

Pacific gray whales (Eschrictius robustus). Journal of Cetacean Research and 

Management 3(1): 19-29. 

Kuehl, D.W. and Haebler, R. 1995. Organochlorine, organobromine, metal, and selenium 

residues in bottlenose dolphins (Tursiops truncatus) collected during an unusual mortality 

even in the Gulf of Mexico, 1990. Archives of Environmental Contamination and 

Toxicology 28: 494-499. 

Lahvis, G.P., Wells, R.S., Kuehl, D.W., Stewart, J.L., Rhinehart, H.L., Via, C.S. 1995. 

Decreased lymphocyte responses in free-ranging bottlenose dolphins (Tursiops truncatus) 

are associated with increased concentrations of PCB’s and DDT in peripheral blood. 

Environmental Health Perspective 103(4): 67-72. 

Law, R.J., Fileman, C.F., Hopkins, A.D., Baker, J.R., Harwood, J., Jackson, D.B., Kennedy, S., 

Martin, A.R., and Morris, R.J. 1991. Concentrations of trace metals in the livers of 

marine mammals (seals, porpoises and dolphins) from waters around the British Isles. 

Marine Pollution Bulletin 22: 183-191. 

Leatherwood, S. and R. R. Reeves. 1983. The Sierra Club Handbook of Whales and Dolphins. 

Sierra Club Books, San Francisco, 302 pp. 

Lipscomb, T.P., Schulman, F.Y., Moffett, D., Kennedy, S. 1994. Morbilliviral disease in Atlantic 

bottlenose dolphins (Tursiops truncatus) from the 1987-1988 epizootic. Journal of 

Wildlife Diseases 30(4): 567-571. 

Lusseau, D. 2005. Residency pattern of bottlenose dolphins Tursiops spp. in Milford Sound, 

New Zealand is related to boat traffic. Marine Ecology Progress Series 295: 265-272. 

Mann, J., Smolker, R.A., Smuts, B.B. 1995. Responses to calf entanglement in free ranging 

bottlenose dolphins. Marine Mammal Science 11(1): 100-106. 
32

McFee, W.E., and Burdett, L.G. 2007. Spatial and temporal analysis of bottlenose dolphin 

strandings in South Carolina, 1992-2005. NOAA Technical Memorandum NOS NCCOS 

46. 12pp. 

McFee, W.E., and Hopkins-Murphy, S.R. 2002. Bottlenose dolphin (Tursiops truncatus)

 strandings in South Carolina, 1992-1996. Fishery Bulletin 100: 258-265. 

McFee, W.E., Hopkins-Murphy, S.R., and Schwacke, L.H. 2006. Trends in bottlenose dolphin 

(Tursiops truncatus) strandings in South Carolina, USA, 1997-2003: implications for the 

Southern North Carolina and South Carolina Management Units. Journal of Cetacean 

Research and Management 8(2): 195-201. 

Miller, M. 1993. The rise of coastal and marine tourism. Ocean and Coastal Management. 21: 

183-199. 

Miller, M.A., Gardner, I.A., Kreuder, C., Paradies, D.M., Worcester, K.R., Jessup, D.A. 2002. 

Coastal freshwater runoff is a risk factor for Toxoplasma gondii infection of southern sea 

otters (Enhydra lutris nereis). International Journal of Parasitology 32: 997-1006. 

National Ocean and Atmospheric Administration (NOAA). 2001. Private docks: Fighting for the 

public’s rights in New York. Coastal Services Center: linking people, information, and 

technology 4(6): 4-6. 

National Ocean and Atmospheric Administration (NOAA). 2009. Marine Mammal Health and 

Stranding Response Program (MMHSRP). http://www.nmfs.noaa.gov/pr/health/. 

Accessed March 29, 2010. 

National Ocean and Atmospheric Administration (NOAA). 2010. 2010 Atlantic Ocean, Gulf of 

Mexico, and Caribbean Category I and II Fisheries under the Marine Mammal 

Authorization Program (for State and Federal Waters).
33

http://sero.nmfs.noaa.gov/pr/mm/MMAP%202010/MMAP%20Category%20I%0and%20

II%20Fisheries%20201012-2-09jpfinal-1.pdf. Accessed March 29, 2010. 

National Oceanic and Atmospheric Administration (NOAA). 2009. Bottlenose Dolphin 

(Tursiops truncatus).

http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/bottlenosedolphin.htm

Accessed March 28, 2010. 

National Oceanic and Atmospheric Administration (NOAA). 2009. Bottlenose Dolphin

 (Tursiops truncatus) Charleston Estuarine Systems Stock.

http://www.nmfs.noaa.gov/pr/pdfs/sars/ao2009dobn-ces.pdf. Accessed March 28, 2010. 

Noke, W.D. and Odell, D.K. 2002. Interactions between the Indian River Lagoon blue crab 

fishery and the bottlenose dolphin, Tursiops truncatus. Marine Mammal Science 18(4): 

819-832. 

Norman, S.A., Bowlby, C.E., Brancato, M.S., Calambokidis, J., Duffield, D., Gearin, P.J., 

Gornall, T.A., Gosho, M.E., Hanson, B., Hodder, J., Jeffries, S.J., Lagerguist, 

B.,Lambourn, D.M., Mate, B., Norberg, B., Osborne, R.W., Rash, J.A., Riemer, S., 

Scordino, J. 2004. Cetacean strandings in Oregon and Washington between 1930 and 

2002. Journal of Cetacean Research and Management 6(1): 87-99. 

Northridge, S.P. 1984. World review of interactions between marine mammals and fisheries. 

Rome: Food and Agriculture Organization of the United Nations. FAO Fish Pap. 251:1-

190. 

Northridge, S.P. and Hofman, R.J. 1999. Marine mammal interactions with fisheries. In: Twiss 

J.R. Jr, Reeves R.R., editors. Conservation and management of marine mammals. 

Washington, DC: Smithsonian Institution Press. 99-119. 
34

Nowacek, S.M., Wells, R.S., Solow, A.R. 2001. Short-term effects of boat traffic on bottlenose 

dolphins, Tursiops truncatus, in Sarasota Bay, Florida Society for Marine Mammalogy

17(4): 673-688. 

Nowacek, D.P., Thorne, L.H., Johnston, D.W., Tyack, P.L. 2007. Responses of cetaceans to 

anthropogenic noise. Mammal Review 37(2): 81-115. 

Ramsey, F.L and Schafer, D.W. The Statistical Sleuth: A Course in Methods of Data

 Analysis. California: Duxbury, 2002. Print. 

Read, A.J. 2008. The looming crisis: interactions between marine mammals and fisheries. 

Journal of Mammalogy 89(3): 541-548. 

Read, A.J., Drinker, P., Northridge, S. 2006. Bycatch of marine mammals in U.S. and global 

fisheries. Conservation Biology 20: 163-169. 

Read, A.J., Waples, D.M., Urian, K.W., Swanner, D. 2003. Fine-scale behavior of bottlenose 

dolphins around gillnets. Proceedings of the Royal Society London 270:S90-S92. 

Ross, P.S., DeSwart, R.L., Reijnders, P.J.H., Van Loveren, H., Vos, J.G., Osterhaus, A.D.M.E. 

1995. Contaminant-related suppression of delayed-type hypersensitivity and antibody 

responses in harbor seals fed herring from the Baltic Sea. Environmental Health 

Perspective 103: 162-167. 

Schwacke, L.H., Eberhard, O.V., Hansen, L.H., Wells, R.S., Mitchum, G.B., Hohn, A.A., Fair, 

P.A. 2002. Probabilistic risk assessment of reproductive effects of polychlorinated 

biphenyls on bottlenose dolphins (Tursiops truncatus) from the southeast United States 

coast. Environmental Toxicology and Chemistry 21(12): 2752-2764. 

Speakman, T., Zolman, E., Adams, J., Defran, R.H., Laska, D., Schwacke, L., Craigie, J., Fair, P. 

2006. Temporal and spatial aspects of bottlenose dolphin occurrence in coastal and 
35

estuarine waters near Charleston, South Carolina. NOAA Technical Memorandum NOSNCCOS-37. 50 pp. 

Stoddard, R.A., Delong, R.L., Byrne, B.A., Jange, S., Gulland, F.M.D. 2008. Prevalence and 

characterization of Salmonella spp. among marine animals in the Channel Islands, 

California. Diseases of Aquatic Organisms 81: 5-11. 

Vos, J.G. and Roij, J. 1972. Immunosuppressive activity of a polychlorinated biphenyl

 preparation on the humoral immune response in guinea pigs. Toxicology and Applied

Pharmacology 21:549. 

Wells, R.S. 1993. The marine mammals of Sarasota Bay. Pages 9.1-9.23 in P. Roat, C. 

Ciciccolella, H. Smith and D. Tomasko, eds. Sarasota Bay: 1992 Framework for Action. 

Published by the Sarasota National Estuary Program, 5333 N. Tamiami Trail, Sarasota, 

Florida. 

Wells, R.S., and Scott, M.D. 1997. Seasonal incidence of boat strikes on bottlenose dolphins near 

Sarasota, Florida. Marine Mammal Science 13(3): 475-480. 

Wells, R.S., Hofmann, S., and Moors, T.L. 1998. Entanglement and mortality of bottlenose 

dolphins, Tursiops truncatus, in recreational fishing gear in Florida. Fishery Bulletin 96: 

647-650. 

Wells, R.S., Allen, J.B., Hoffman, S., Bassos-Hull, K., Fauquier, D.A., Barros, N.B., DeLynn,

R.E., Sutton, G., Socha, V. and M.D. Scott. 2008. Consequences of injuries on survival 

and reproduction of common bottlenose dolphins (Tursiops truncatus) along the west 

coast of Florida. Marine Mammal Science 24: 774-794. 
36

Wilson, B., Thompson, P. M. and P. S. Hammond. 1997. Habitat use by bottlenose dolphins: 

seasonal distribution and stratified movement patterns in the Moray Firth, Scot land. 

Journal of Applied Ecology 34:1365–1374.

Zolman, E.S. 2002. Residence patterns of bottlenose dolphins (Tursiops truncatus) in the Stono 

River estuary, Charleston County, South Carolina, U.S.A. Marine Mammal Science

18(4): 879-892. 
37

Tables
38

Table 1. Summary of predicted urban growth in the Charleston region from 1994 to 2030 (Allen 

and Lu 2003). 

Items BCD Region Berkeley Charleston Dorchester

Population Growth

Population 1994 (in person) 532,688 138,776 307,468 86,444

Population 2030 (in person) 795,879 200,000 469,346 126,533

Net Growth 263,211 161,224 161,878 40,089

Change +49.41% +44.12% +52.65% +46.38%

Annual Growth Rate +1.37% +1.23% +1.46% +1.29%

Urban Area Growth

Urban Area 1994 (mile2) 250.07 81.61 126.50 41.96

Urban Area 2030 (mile2) 867.60 306.41 361.33 199.86

Net Growth 603.53 224.80 234.83 157.90

Change +246.94% +275.46% +185.64% +376.31%

Annual Growth Rate +6.85% +7.65 +5.15% +10.45%

Population vs. Urban Area

Population Density 1994 (person/ mile2) 2030 1700 2431 2060

Population Density 2030 (person/ mile2) 917 652 1299 633

Change -54.83% -61.65% -46.57% -69.27%

Per Capita Urban Area 1994 (acres) 0.30 0.38 0.26 0.31

Per Capita Urban Area 2030 (acres) 0.70 0.98 0.49 1.01

Change +133.33% +158.03% +88.46% +225.81%

Sprawl Index (growth ratio) 5:1 6.24:1 3.53:1 8.11:1
39

Table 2. Pearson correlations and associated p-values for strandings and various license data for 

Charleston County and South Carolina. 

 

Comparison Pearson Correlation p-value

Charleston County

Strandings vs. boat licenses 0.021 0.960

Strandings vs. HI strandings -0.216 0.607

Strandings vs. commercial fishing licenses -0.104 0.806

Strandings vs. recreational fishing licenses 0.395 0.605

Strandings vs. crab pot licenses -0.376 0.358

HI strandings vs. boat licenses -0.137 0.746

HI strandings vs. commercial fishing licenses 0.128 0.763

HI strandings vs. recreational fishing licenses -0.595 0.405

HI strandings vs. crab pot licenses 0.431 0.287

Boat licenses vs. commercial fishing licenses -0.676 0.066

Boat licenses vs. recreational fishing licenses -0.711 0.289

Boat licenses vs. crab pot licenses 0.069 0.810

Commercial fishing licenses vs. recreational fishing licenses 0.671 0.329

Commercial fishing licenses vs. crab pot licenses 0.473 0.237

Recreational fishing licenses vs. crab pot licenses -0.493 0.507

South Carolina

Strandings vs. crab pot licenses -0.206 0.624

HI strandings vs. crab pot licenses 0.562 0.147

Strandings vs. HI strandings 0.007 0.988
40

Figures
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Figure 1. Bottlenose dolphin showing propeller wounds after being struck by a boat.

Figure 2. Bottlenose dolphin with evidence of fishing line entanglement around tail. 
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Figure 3. Beaked whale with hook and line in lower jaw. 

Figure 4. Projected population growth for Charleston, SC (Allen and Lu 2003). 
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Figure 5. Trends in stranding density in Charleston County divided into four year intervals from 

1994-2009. 
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Figure 6. The trends between dock permit density and bottlenose dolphin strandings in 

Charleston County divided into four year intervals from 1994-2009. 
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Figure 7. Trends in residential growth (in polygon form) and trends in bottlenose dolphin 

stranding density in Charleston County divided into four year intervals from 1994-2009. 
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Figure 8. Trends in residential growth (after conversion to points) and trends in bottlenose 

dolphin stranding density in Charleston County divided into four year intervals from 1994-2009. 
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Figure 9. Statistical significance between the trends in docks and bottlenose dolphin strandings in 

Charleston County divided into four year intervals from 1994-2009. 
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Figure 10. Statistical significance between trends in residential growth and bottlenose dolphin 

strandings in Charleston County divided into four year intervals from 1994-2009. 
49

Figure 11. Total bottlenose dolphin strandings in South Carolina (black bars) plotted with the 

number of bottlenose dolphin strandings in Charleston County (open bars). 
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Figure 12. Total annual bottlenose dolphin strandings in South Carolina (black bars) plotted with 

annual bottlenose dolphin strandings in Charleston County (open bars), 1994-2009. 
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Figure 13. Total number of bottlenose dolphins with human interaction in South Carolina (black 

bars) plotted with bottlenose dolphins with human interaction in Charleston County (open bars). 
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Figure 14. Annual number of bottlenose dolphin strandings with human interaction in South 

Carolina (black bars) plotted with annual number of bottlenose dolphin strandings in Charleston 

County (open bars). 
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Figure 15. Annual number of crabpot fishery permits (black bars) in South Carolina plotted with 

annual bottlenose dolphin strandings in South Carolina (open bars), 2002-2009. 
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Figure 16. Annual number of crabpot fishery permits (black bars) in Charleston County plotted 

with annual bottlenose dolphin strandings in Charleston County (open bars), 2002-2009. 
55

Figure 17. Trends in commercial fishing licenses in Charleston County from 2002 to 2009. 
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Figure 18. Trends in issued boat licenses in Charleston County from 2002 to 2009. 

United States Department of Commerce

Gary F. Locke

 Secretary

National Oceanic and Atmospheric Administration

Jane Lubchenco

Under Secretary of 

Commerce for Oceans and Atmosphere, 

NOAA Administrator 

National Ocean Service

David Kennedy

Assistant Administrator (Acting)